Program - Brookhaven National Laboratory
Program - Brookhaven National Laboratory
Program - Brookhaven National Laboratory
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
as Monte Carlo simulations, and includes an estimation of the systematic uncertainties in the mentioned<br />
quantities. The overall efficiency of the experimental program and the range of possible measurements will<br />
be expanded in the near future with the construction of a second experimental area (EAR-2), vertically<br />
located 20 m on top of the present n TOF spallation target. This upgrade, which will benefit from a<br />
neutron flux 25 times higher than the existing one, will provide a substantial improvement in measurement<br />
sensitivities and will open the possibility to measure neutron cross-section of isotopes with very short halflives<br />
or available in very small quantities. The technical study for the construction of this new neutron<br />
beam will be presented, highlighting the main advantages compared to the presently existing Experimental<br />
Area (EAR-1).<br />
HA 2 4:00 PM<br />
Measurement of the Neutron Capture Cross Section of the Fissile Isotope 235 U with the<br />
CERN n TOF Total Absorption Calorimeter and a Fission Tagging Based on Micromegas<br />
Detectors<br />
D. Cano Ott, E. Mendoza<br />
Centro de Investigaciones Energeticas, Mediambientales y Tecnologicas - CIEMAT, Spain<br />
C. Guerrero<br />
CERN, Geneva, Switzerland<br />
E. Berthoumieux<br />
CEA, Saclay, France<br />
and the<br />
n TOF collaboration<br />
Actual and future nuclear technologies require more accurate nuclear data on the (n,γ) cross sections<br />
and α-ratios of fissile isotopes [1,2]. Their measurement presents several difficulties, mainly related to<br />
the strong fission γ-ray background competing with the weaker γ-ray cascades used as the experimental<br />
signature of the (n,γ) process. A specific setup [3] has been used at the CERN n TOF facility in 2012<br />
for the measurement of the (n,γ) cross section and α-ratios of fissile isotopes and used for the case of the<br />
235 U isotope. The setup consists in a set of micromegas fission detectors [4] surrounding the 235 U samples<br />
and placed inside the segmented BaF2 Total Absorption Calorimeter [5]. At the time of the conference<br />
we will present the details of the measurement, the methodology used for the data analysis, based both<br />
on experimental corrections and GEANT4 Monte Carlo simulations, and preliminary results on the (n,γ)<br />
cross section and the α-ratios. As a side product of the analysis, the experimental data will serve to test<br />
the validity of several models for predicting the γ-ray emission in the (n,γ) and (n,f) reactions.<br />
[1] M. Salvatores and R. Jacqmin, Uncertainty and target accuracy assessment for innovative system using<br />
recent covariance data evaluations, ISBN 978-92-64-99053-1, NEA/WPEC-26 (2008) [2] NEA High Priority<br />
Request List www.nea.fr/dbdata/hprl/ [3] C. Guerrero et al., Simultaneous measurement of neutroninduced<br />
capture and fission reactions at CERN, Eur. Phys. J. A 48, 3 (2012) 29 [4] S. Andriamonje et<br />
al., A transparent detector for n TOF neutron beam monitoring, Journal of the Korean Physical Society<br />
59, (2011) 1597-1600 [5] C. Guerrero et al., The n TOF Total Absorption Calorimeter for neutron capture<br />
measurements at CERN, Nucl. Instr. and Meth. A 608 (2009) 424-433.<br />
HA 3 4:20 PM<br />
Measurement of the 238 U Radiative Capture Cross Section with C6D6 at the n TOF CERN<br />
Facility<br />
104
Change language